IIW History 1948-1958

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to obtain is that concerning the stresses actually carried in service by the con– structions in which the failures occurred. Consequently, the Commission has thought it necessary to collect documentary information on statistical extenso– meters (or counters) which make it possible to estimate how often t he various stress levels are exceeded. vVhen the Commission has received this information, it hopes to be able to give useful guidance to manufacturers and use rs in the selection of apparatus for use in the study of the service performance of various welded constructions subjected to fatigue. D . Application of statistical methods to the interpretation of fatigue tests. From 1955 on, Commi ssion XIII has received from a n umber of its member. various documents on the statistical interpretation of the results provided by fatigue tests. The Commission ha s therefo re set up a \\'Orking group respo nsibl e for preparing a general report giving the present position on thi · question a nd taking account in particular of the \\"Ork of the American Society for Te::;ting lVIateri als (ASTlVI) which is preparing a special booklet on the question. E . Allied processes. Apart from welding properly speaking, Corn mission XII I is, as mentioned above, concerned with allied processes, such as oxygen cutting and building-up , in so far as these t echniques may influence fatigue strength. The Commi sion has not so far carried out a ny organi eel "·ork on oxygen cutting . However, as a result of the exchange of information on national testin (J' programmes \vhich it carries out every year , the Commission has been informed of \\·ork in hand on this subject, in particular in France and the United Kingdom ; it has thus been possible to coordinate this \\"Ork so that there is i:o overlapping. The study of the influence of building up is a consequence of the investiga– tion on fatigue failures mentioned above . I n fact , when this investigation was launched, it seemed that it \Yould be easier to obtain results in connexion with the use of \Yelding for repairs than for actual construction; the Commis ion therefore put on its agenda the study of the influence of building-up by \Yelding on behaviour in service so that the conditions t o be ob. erved, in order that building-up might be ati factory, could be deduced. As a result of this decision, the Commission had received by the Zurich assembly in 1955 several documents dealing with cases of fatigue failures in part: which had been built up by welding. The opinions expressed in these different documents were far from being in agreement with one another and it was seen in several countries to be necessary to plan a systematic experimental study on the fatigue strength of parts built up by welding or even by other processes . The programme for this investigation was jointly drawn up by France, the Nether– lands and the United Kingdom. The other member countries of the Commission will be informed of it so that they may eventually be able to contribute. The tests undertaken in this connexion are at present being carried out a nd the results will no doubt soon be submitted t o the Commission. + FUTURE PROGRAMME AND CONCLUSION. A certain number of the matters mentioned above have not yet reached the stage where definitive conclusions can be put forward by the Commission and so they still remain upon the programme of future work. In addition, problems which have already been considered will have to be reviewed in relation to the evolution of the welding proce ·ses and of testing techniques. ·with regard to new and important matters, mention must be made of the